Just found a box of old radio spares , a few old triodes , an interstage transformer , caps and pots/rheostats ,
'Balloon' valves , stunningly beautifull bright chrome gettering , transformer 3.5:1 , looks like theres easily the makings of a preamp and also spares to help renovate my Marconiphone preamp .
Loudspeakers of the time were typically a very tiny headphone speaker attached to the conventional horn type apparatus found on a gramaphone , around 500 mW output power with 2 or 5% distortion was sufficient ,the drive units were usually in the range of 1-2kohms ,these era of audio transformer should work fairly well into a modern mic input or 10k balanced load , it will be fun to test what the cores in these very first generation audio transformers.
'Balloon' valves , stunningly beautifull bright chrome gettering , transformer 3.5:1 , looks like theres easily the makings of a preamp and also spares to help renovate my Marconiphone preamp .
Loudspeakers of the time were typically a very tiny headphone speaker attached to the conventional horn type apparatus found on a gramaphone , around 500 mW output power with 2 or 5% distortion was sufficient ,the drive units were usually in the range of 1-2kohms ,these era of audio transformer should work fairly well into a modern mic input or 10k balanced load , it will be fun to test what the cores in these very first generation audio transformers.